Public bug reported: After upgrading kubuntu from 15.10 to 16.04, my system no longer boots to the login screen. There is a lot of flickering and the kubuntu logo is sometimes shown, sometimes a black screen. I am able to login to a terminal tty and see the following line from dmesg:
sddm[3968]: segfault at 0 ip 00007f31f9a776c3 sp 00007fff6b1c9b60 error 4 in libQt5Core.so.5.5.1 I discovered that removing the nvidia driver package resolves the situation and makes it possible to login to the desktop again. However, that makes it impossible for me to use my Nvidia graphics device. I have a laptop with an Intel skylake CPU (i5-6200U) and an Nvidia Geforce 940M graphics card. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: kubuntu-desktop 1.338 ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6 Uname: Linux 4.4.0-21-generic x86_64 NonfreeKernelModules: zfs zunicode zcommon znvpair zavl ApportVersion: 2.20.1-0ubuntu2 Architecture: amd64 CurrentDesktop: KDE Date: Sat Apr 30 20:59:40 2016 InstallationDate: Installed on 2016-02-03 (87 days ago) InstallationMedia: Error: [Errno 13] Permission denied: '/var/log/installer/media-info' SourcePackage: kubuntu-meta UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: kubuntu-meta (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug xenial -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1577041 Title: Cannot login to kubuntu after upgrade To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/kubuntu-meta/+bug/1577041/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs